Dietary energy and protein levels on lactation performance and progeny growth of Hu sheep

Abstract

ABSTRACT This experiment aimed to investigate the effects of dietary energy or protein levels on lactation performance and progeny growth of Hu sheep. Thirty early lactation ewes with twin litters were assigned into five treatments (E1, E2 = P2, E3, P1, P3; n = 6) according to dietary energy levels (E1: 9.52 MJ/kg, E2: 10.02 MJ/kg, E3: 10.52 MJ/kg) and dietary protein levels (P1: 9.82%, P2: 10.99%, P3: 12.11%). The corresponding lambs were divided into SE1, SE2 = SP2, SE3, SP1 and SP3 (n = 12). Dietary energy level significantly affected the average daily gain (ADG) of Hu sheep (P = .005). The milk yield increased significantly with the increase of dietary protein level (P = .017), and then significantly increased the ADG of lambs. The serum blood urea nitrogen (BUN) of offspring (P = .006) and ewes (P = .003) increased significantly with the increase in the dietary protein level of ewes. Interestingly, at 60 d, the body size of SE3 group was the highest, and the straight crown hip length (P = .005) with the lightest birth weight (SP2) was significantly higher than the other two groups. To sum up, we suggest that Hu sheep be fed diets with energy and protein levels of 10.52 MJ/kg and 10.99%, respectively.